Lubricating grease with high water resistance

Abstract

The present invention relates to lubricating greases comprising at least one thickening agent and at least one lubricating oil, wherein the lubricating grease contains at least one polymeric structure improver that can be obtained by polymerization of monomer compositions, which are composed of a) 0 to 40 wt %, relative to the weight of the monomer compositions for synthesis of the polymeric structure improvers, of at least one (meth)acrylate of formula (I) in which R represents hydrogen or methyl, R 1 denotes a straight-chain or branched alkyl moiety having 1 to 5 carbon atoms, b) 40 to 99.99 wt %, relative to the weight of the monomer compositions for synthesis of the polymeric structure improvers, of at least one (meth)acrylate of formula (II) in which R represents hydrogen or methyl, R 2 denotes a straight-chain or branched alkyl moiety having 6 to 30 carbon atoms, c) 0.01 to 20 wt %, relative to the weight of the monomer compositions for synthesis of the polymeric structure improvers, of monomers containing acid groups or salts thereof, d) 0 to 59.99 wt %, relative to the weight of the monomer compositions for synthesis of the polymeric structure improvers, of comonomer.

1. A lubricating grease comprising at least one thickening agent, at least one lubricating oil, and at least one polymeric structure improver that can be obtained by polymerization of monomer compositions, which comprise
 a) 0 to 40 wt %, relative to the weight of the monomer compositions for synthesis of the polymeric structure improvers, of at least one (meth)acrylate of formula (I) 
 
       
         
           
           
               
               
           
         
       
       in which R represents hydrogen or methyl, R 1  denotes a straight-chain or branched alkyl moiety having 1 to 5 carbon atoms,
 b) 40 to 99.99 wt %, relative to the weight of the monomer compositions for synthesis of the polymeric structure improvers, of at least one (meth)acrylate of formula (II) 
 
       
         
           
           
               
               
           
         
       
       in which R represents hydrogen or methyl, R 2  denotes a straight-chain or branched alkyl moiety having 6 to 30 carbon atoms,
 c) 0.01 to 5 wt %, relative to the weight of the monomer compositions for synthesis of the polymeric structure improvers, of monomers containing acid groups or salts thereof, 
 d) 0 to 59.99 wt %, relative to the weight of the monomer compositions for synthesis of the polymeric structure improvers, of comonomer. 
 
     
     
       2. A lubricating grease according to  claim 1 , wherein at least part of the monomers according to component c) contains at least one carboxyl group, at least one phosphonic acid group and/or at least one sulfonic acid group. 
     
     
       3. A lubricating grease according to  claim 2 , wherein component c) contains at least one monomer selected from the group comprising methacrylic acid and/or acrylic acid or salts thereof. 
     
     
       4. A lubricating grease according to  claim 1 , wherein the monomer composition contains 0.1 to 5 wt % relative to the weight of the monomer compositions for synthesis of the polymeric structure improvers, of monomers containing acid groups or salts thereof according to component c). 
     
     
       5. A lubricating grease according to  claim 1 , wherein the polymeric structure improver has a weight-average molecular weight ranging from 15,000 g/mol to 1,000,000 g/mol. 
     
     
       6. A lubricating grease according to  claim 1 , wherein the thickener is a soap thickener, an inorganic thickener and/or a polymeric organic thickener. 
     
     
       7. A lubricating grease according to  claim 1 , wherein the lubricating grease contains additives. 
     
     
       8. A lubricating grease according to  claim 1 , wherein the lubricating grease has a water resistance of 1 to 50%. 
     
     
       9. A lubricating grease according to  claim 1 , wherein the lubricating grease has a cone penetration ranging from 175 dmm to 385 dmm. 
     
     
       10. A lubricating grease according to  claim 1 , wherein the polymeric structure improver contains a block copolymer. 
     
     
       11. A lubricating grease according to  claim 10 , wherein the polymeric structure improver can be obtained by graft polymerization, wherein a composition comprising components a) to d) is polymerized on a graft base, which comprises an olefin copolymer (OCP) formed mainly from ethylene and propylene and/or a hydrogenated copolymer (HSD) of dienes and styrene. 
     
     
       12. A lubricating grease according to  claim 1 , wherein the lubricating grease contains 1 to 30 wt % of thickener. 
     
     
       13. A lubricating grease according to  claim 1 , wherein the lubricating grease contains 69.9 to 98.9 wt % of lubricating oil. 
     
     
       14. A method for production of lubricating grease, comprising producing a mixture comprising at least one thickening agent, at least one lubricating oil and a polymeric structure improver, which can be obtained by polymerization of monomer compositions, which comprise
 a) 0 to 40 wt %, relative to the weight of the monomer compositions for synthesis of the polymeric structure improvers, of one or more ethylenically unsaturated ester compounds of formula (I) 
 
       
         
           
           
               
               
           
         
       
       in which R represents hydrogen or methyl, R 1  denotes a straight-chain or branched alkyl moiety having 1 to 5 carbon atoms,
 b) 40 to 99.99 wt %, relative to the weight of the monomer compositions for synthesis of the polymeric structure improvers, of one or more ethylenically unsaturated ester compounds of formula (II) 
 
       
         
           
           
               
               
           
         
       
       in which R represents hydrogen or methyl, R 2  denotes a straight-chain or branched alkyl moiety having 6 to 30 carbon atoms,
 c) 0.01 to 20 wt %, relative to the weight of the monomer compositions for synthesis of the polymeric structure improvers, of monomers containing acid groups or salts thereof, 
 d) 0 to 59.99 wt %, relative to the weight of the monomer compositions for synthesis of the polymeric structure improvers, of comonomer. 
 
     
     
       15. A method according to  claim 14 , wherein the polymeric structure improver is added to a dispersion that has a grease structure and that comprises at least one thickening agent and at least one lubricating oil. 
     
     
       16. A method according to  claim 14 , wherein the polymeric structure improver is added in a composition that is liquid at 25° C. to the dispersion. 
     
     
       17. A method according to  claim 15 , wherein the polymeric structure improver is added in a composition that is liquid at 25° C. to the dispersion.